1. Field
Embodiments of the present invention relate to an information recording device and an information recording method for recording information onto a recording medium.
2. Description of the Related Art
In recent years, various technologies have been developed for realizing an increased storage capacity of a magnetic disc device (hereinafter, also referred to as HDD) as an example of the information recording device. Among these is a recording technology called “shingled write recording”. The shingled write recording is a recording method in which, when information is recorded onto a magnetic disc, a recording track is recorded so as to overlap part of an adjacent track. The adoption of the shingled write recording enables the TPI (track per inch) to be further improved.
In the shingled write recording, track groups (hereinafter, also referred to as bands) each including a plurality of adjacent tracks are defined as recording units. Moreover, at least one information recordable band is reserved as a spare band. When information recorded in a band is updated (rewritten), the information to be updated is rewritten not to the band from which the information is read but to the spare band. Then, the band where the information to be updated was recorded is used as a new spare band. That is, in the shingled write recording, the position of the spare band moves from one place to another.
Moreover, with the HDD, a problem called ATI (adjacent track interference) that influences the retention of information of a track adjacent to a recording track sometimes occurs due to a magnetic interference from the recording track. There are cases where the stored information is destroyed by the ATI. For example, the higher the TPI is as in the shingled write recording, the more significant the problem of ATI is. Therefore, it has been performed to make the width of the track at the boundary with the adjacent band wider than that of the other tracks included in this band to thereby avoid the influence of the ATI on the boundary track from the adjacent track of the adjacent band. In other words, there are cases where the track at the boundary with the adjacent band has a structure including a track having the same width as the other tracks included in this band and a protective track having a predetermined width.